import java.util.AbstractList;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.ConcurrentModificationException;
import java.util.Iterator;
import java.util.List;
import java.util.ListIterator;
import java.util.NoSuchElementException;
import java.util.RandomAccess;

/**
 * 
 */

/**
 * @author Navin
 * @param <E>
 * 
 */
/*
 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

/**
 * Awesome implementation of the <tt>List</tt> interface. Implements everything
 * <tt>ArrayList</tt> implements. In addition to extending <tt>ArrayList</tt>,
 * this class provides methods to manipulate the size, and lets you use it like
 * a hashtable. (This class is roughly equivalent to <tt>ArrayList</tt>, except
 * that it is better.)
 * <p>
 * This class is a member of the <a href="{@docRoot}
 * /../technotes/guides/collections/index.html"> Java Collections Framework</a>.
 * 
 * @author Navin Shajan
 * @author Josh Bloch
 * @author Neal Gafter
 * @see ArrayList
 * @since now...
 */

public class AArrayList<E> extends ArrayList<E> implements List<E>,
		RandomAccess, Cloneable, java.io.Serializable {
	/**
	 * An optimized version of AbstractList.Itr
	 */
	private class Itr implements Iterator<E> {
		int cursor; // index of next element to return
		int lastRet = -1; // index of last element returned; -1 if no such
		int expectedModCount = modCount;

		final void checkForComodification() {
			if (modCount != expectedModCount)
				throw new ConcurrentModificationException();
		}

		@Override
		public boolean hasNext() {
			return cursor != size;
		}

		@Override
		@SuppressWarnings("unchecked")
		public E next() {
			checkForComodification();
			int i = cursor;
			if (i >= size)
				throw new NoSuchElementException();
			Object[] elementData = AArrayList.this.elementData;
			if (i >= elementData.length)
				throw new ConcurrentModificationException();
			cursor = i + 1;
			return (E) elementData[lastRet = i];
		}

		@Override
		public void remove() {
			if (lastRet < 0)
				throw new IllegalStateException();
			checkForComodification();

			try {
				AArrayList.this.remove(lastRet);
				cursor = lastRet;
				lastRet = -1;
				expectedModCount = modCount;
			} catch (IndexOutOfBoundsException ex) {
				throw new ConcurrentModificationException();
			}
		}
	}

	/**
	 * An optimized version of AbstractList.ListItr
	 */
	private class ListItr extends Itr implements ListIterator<E> {
		ListItr(int index) {
			super();
			cursor = index;
		}

		@Override
		public void add(E e) {
			checkForComodification();

			try {
				int i = cursor;
				AArrayList.this.add(i, e);
				cursor = i + 1;
				lastRet = -1;
				expectedModCount = modCount;
			} catch (IndexOutOfBoundsException ex) {
				throw new ConcurrentModificationException();
			}
		}

		@Override
		public boolean hasPrevious() {
			return cursor != 0;
		}

		@Override
		public int nextIndex() {
			return cursor;
		}

		@Override
		@SuppressWarnings("unchecked")
		public E previous() {
			checkForComodification();
			int i = cursor - 1;
			if (i < 0)
				throw new NoSuchElementException();
			Object[] elementData = AArrayList.this.elementData;
			if (i >= elementData.length)
				throw new ConcurrentModificationException();
			cursor = i;
			return (E) elementData[lastRet = i];
		}

		@Override
		public int previousIndex() {
			return cursor - 1;
		}

		@Override
		public void set(E e) {
			if (lastRet < 0)
				throw new IllegalStateException();
			checkForComodification();

			try {
				AArrayList.this.set(lastRet, e);
			} catch (IndexOutOfBoundsException ex) {
				throw new ConcurrentModificationException();
			}
		}
	}

	private class SubList extends AbstractList<E> implements RandomAccess {
		private final int offset;
		int size;

		SubList(AbstractList<E> parent, int offset, int fromIndex, int toIndex) {
			this.offset = offset + fromIndex;
			this.size = toIndex - fromIndex;
			modCount = AArrayList.this.modCount;
		}

		@Override
		public void add(int index, E e) {
			super.add(index, e);
			// rangeCheckForAdd(index);
			// checkForComodification();
			// parent.add(parentOffset + index, e);
			// modCount = parent.modCount;
			// this.size++;
		}

		@Override
		public boolean addAll(Collection<? extends E> c) {
			return addAll(this.size, c);
		}

		@Override
		public boolean addAll(int index, Collection<? extends E> c) {
			return super.addAll(index, c);
			// rangeCheckForAdd(index);
			// int cSize = c.size();
			// if (cSize == 0)
			// return false;
			//
			// checkForComodification();
			// parent.addAll(parentOffset + index, c);
			// modCount = parent.modCount;
			// this.size += cSize;
			// return true;
		}

		private void checkForComodification() {
			if (AArrayList.this.modCount != modCount)
				throw new ConcurrentModificationException();
		}

		@Override
		public E get(int index) {
			rangeCheck(index);
			checkForComodification();
			return AArrayList.this.elementData(offset + index);
		}

		@Override
		public Iterator<E> iterator() {
			return listIterator();
		}

		@Override
		public ListIterator<E> listIterator(final int index) {
			checkForComodification();
			rangeCheckForAdd(index);
			final int offset = this.offset;

			return new ListIterator<E>() {
				int cursor = index;
				int lastRet = -1;
				int expectedModCount = AArrayList.this.modCount;

				@Override
				public void add(E e) {
					checkForComodification();

					try {
						int i = cursor;
						SubList.this.add(i, e);
						cursor = i + 1;
						lastRet = -1;
						expectedModCount = AArrayList.this.modCount;
					} catch (IndexOutOfBoundsException ex) {
						throw new ConcurrentModificationException();
					}
				}

				final void checkForComodification() {
					if (expectedModCount != AArrayList.this.modCount)
						throw new ConcurrentModificationException();
				}

				@Override
				public boolean hasNext() {
					return cursor != SubList.this.size;
				}

				@Override
				public boolean hasPrevious() {
					return cursor != 0;
				}

				@Override
				@SuppressWarnings("unchecked")
				public E next() {
					checkForComodification();
					int i = cursor;
					if (i >= SubList.this.size)
						throw new NoSuchElementException();
					Object[] elementData = AArrayList.this.elementData;
					if (offset + i >= elementData.length)
						throw new ConcurrentModificationException();
					cursor = i + 1;
					return (E) elementData[offset + (lastRet = i)];
				}

				@Override
				public int nextIndex() {
					return cursor;
				}

				@Override
				@SuppressWarnings("unchecked")
				public E previous() {
					checkForComodification();
					int i = cursor - 1;
					if (i < 0)
						throw new NoSuchElementException();
					Object[] elementData = AArrayList.this.elementData;
					if (offset + i >= elementData.length)
						throw new ConcurrentModificationException();
					cursor = i;
					return (E) elementData[offset + (lastRet = i)];
				}

				@Override
				public int previousIndex() {
					return cursor - 1;
				}

				@Override
				public void remove() {
					if (lastRet < 0)
						throw new IllegalStateException();
					checkForComodification();

					try {
						SubList.this.remove(lastRet);
						cursor = lastRet;
						lastRet = -1;
						expectedModCount = AArrayList.this.modCount;
					} catch (IndexOutOfBoundsException ex) {
						throw new ConcurrentModificationException();
					}
				}

				@Override
				public void set(E e) {
					if (lastRet < 0)
						throw new IllegalStateException();
					checkForComodification();

					try {
						AArrayList.this.set(offset + lastRet, e);
					} catch (IndexOutOfBoundsException ex) {
						throw new ConcurrentModificationException();
					}
				}
			};
		}

		private String outOfBoundsMsg(int index) {
			return "Index: " + index + ", Size: " + this.size;
		}

		private void rangeCheck(int index) {
			if (index < 0 || index >= this.size)
				throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
		}

		private void rangeCheckForAdd(int index) {
			if (index < 0 || index > this.size)
				throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
		}

		@Override
		public E remove(int index) {
			return super.remove(index);
			// rangeCheck(index);
			// checkForComodification();
			// E result = parent.remove(parentOffset + index);
			// modCount = parent.modCount;
			// this.size--;
			// return result;
		}

		@Override
		protected void removeRange(int fromIndex, int toIndex) {
			super.removeRange(fromIndex, toIndex);
			// checkForComodification();
			// parent.removeRange(parentOffset + fromIndex, parentOffset +
			// toIndex);
			// modCount = parent.modCount;
			// this.size -= toIndex - fromIndex;
		}

		@Override
		public E set(int index, E e) {
			rangeCheck(index);
			checkForComodification();
			E oldValue = AArrayList.this.elementData(offset + index);
			AArrayList.this.elementData[offset + index] = e;
			return oldValue;
		}

		@Override
		public int size() {
			checkForComodification();
			return this.size;
		}

		@Override
		public List<E> subList(int fromIndex, int toIndex) {
			AArrayList.subListRangeCheck(fromIndex, toIndex, size);
			return new SubList(this, offset, fromIndex, toIndex);
		}
	}

	private static final long serialVersionUID = 8683452581122892189L;

	private static int hugeCapacity(int minCapacity) {
		if (minCapacity < 0) // overflow
			throw new OutOfMemoryError();
		return minCapacity > AArrayList.MAX_ARRAY_SIZE ? Integer.MAX_VALUE
				: AArrayList.MAX_ARRAY_SIZE;
	}

	/**
	 * The array buffer into which the elements of the AArrayList are stored.
	 * The capacity of the AArrayList is the length of this array buffer.
	 */
	private transient Object[] elementData;

	/**
	 * The size of the AArrayList (the number of elements it contains).
	 * 
	 * @serial
	 */
	private int size;

	/**
	 * The maximum size of array to allocate. Some VMs reserve some header words
	 * in an array. Attempts to allocate larger arrays may result in
	 * OutOfMemoryError: Requested array size exceeds VM limit
	 */
	private static final int MAX_ARRAY_SIZE = Integer.MAX_VALUE - 8;

	static void subListRangeCheck(int fromIndex, int toIndex, int size) {
		if (fromIndex < 0)
			throw new IndexOutOfBoundsException("fromIndex = " + fromIndex);
		if (toIndex > size)
			throw new IndexOutOfBoundsException("toIndex = " + toIndex);
		if (fromIndex > toIndex)
			throw new IllegalArgumentException("fromIndex(" + fromIndex
					+ ") > toIndex(" + toIndex + ")");
	}

	/**
	 * Constructs an empty list with an initial capacity of ten.
	 */
	public AArrayList() {
		this(10);
	}

	/**
	 * Constructs a list containing the elements of the specified collection, in
	 * the order they are returned by the collection's iterator.
	 * 
	 * @param c
	 *            the collection whose elements are to be placed into this list
	 * @throws NullPointerException
	 *             if the specified collection is null
	 */
	public AArrayList(Collection<? extends E> c) {
		elementData = c.toArray();
		size = elementData.length;
		// c.toArray might (incorrectly) not return Object[] (see 6260652)
		if (elementData.getClass() != Object[].class)
			elementData = Arrays.copyOf(elementData, size, Object[].class);
	}

	/**
	 * Constructs an empty list with the specified initial capacity.
	 * 
	 * @param initialCapacity
	 *            the initial capacity of the list
	 * @throws IllegalArgumentException
	 *             if the specified initial capacity is negative
	 */
	public AArrayList(int initialCapacity) {
		super();
		if (initialCapacity < 0)
			throw new IllegalArgumentException("Illegal Capacity: "
					+ initialCapacity);
		this.elementData = new Object[initialCapacity];
	}

	/**
	 * Appends the specified element to the end of this list.
	 * 
	 * @param e
	 *            element to be appended to this list
	 * @return <tt>true</tt> (as specified by {@link Collection#add})
	 */
	@Override
	public boolean add(E e) {
		ensureCapacityInternal(size + 1); // Increments modCount!!
		elementData[size++] = e;
		return true;
	}

	/**
	 * Inserts the specified element at the specified position in this list.
	 * Shifts the element currently at that position (if any) and any subsequent
	 * elements to the right (adds one to their indices).
	 * 
	 * @param index
	 *            index at which the specified element is to be inserted
	 * @param element
	 *            element to be inserted
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	@Override
	public void add(int index, E element) {
		rangeCheckForAdd(index);

		ensureCapacityInternal(size + 1); // Increments modCount!!
		System.arraycopy(elementData, index, elementData, index + 1, size
				- index);
		elementData[index] = element;
		size++;
	}

	/**
	 * Appends all of the elements in the specified collection to the end of
	 * this list, in the order that they are returned by the specified
	 * collection's Iterator. The behavior of this operation is undefined if the
	 * specified collection is modified while the operation is in progress.
	 * (This implies that the behavior of this call is undefined if the
	 * specified collection is this list, and this list is nonempty.)
	 * 
	 * @param c
	 *            collection containing elements to be added to this list
	 * @return <tt>true</tt> if this list changed as a result of the call
	 * @throws NullPointerException
	 *             if the specified collection is null
	 */
	@Override
	public boolean addAll(Collection<? extends E> c) {
		Object[] a = c.toArray();
		int numNew = a.length;
		ensureCapacityInternal(size + numNew); // Increments modCount
		System.arraycopy(a, 0, elementData, size, numNew);
		size += numNew;
		return numNew != 0;
	}

	/**
	 * Inserts all of the elements in the specified collection into this list,
	 * starting at the specified position. Shifts the element currently at that
	 * position (if any) and any subsequent elements to the right (increases
	 * their indices). The new elements will appear in the list in the order
	 * that they are returned by the specified collection's iterator.
	 * 
	 * @param index
	 *            index at which to insert the first element from the specified
	 *            collection
	 * @param c
	 *            collection containing elements to be added to this list
	 * @return <tt>true</tt> if this list changed as a result of the call
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 * @throws NullPointerException
	 *             if the specified collection is null
	 */
	@Override
	public boolean addAll(int index, Collection<? extends E> c) {
		rangeCheckForAdd(index);

		Object[] a = c.toArray();
		int numNew = a.length;
		ensureCapacityInternal(size + numNew); // Increments modCount

		int numMoved = size - index;
		if (numMoved > 0)
			System.arraycopy(elementData, index, elementData, index + numNew,
					numMoved);

		System.arraycopy(a, 0, elementData, index, numNew);
		size += numNew;
		return numNew != 0;
	}

	/**
	 * Replaces the element at the specified position in this list with the
	 * specified element. If this list's size is less than index+1, null
	 * elements are added until they are equal and then the element is added.
	 * 
	 * @param index
	 *            index of the element to replace
	 * @param element
	 *            element to be stored at the specified position
	 * @return the element previously at the specified position or null if size
	 *         is less than index+1
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	public E ASet(int index, E element) {
		if (index < 0)
			throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
		if (index > this.size) {
			ensureCapacity(index + 1);
			while (index > this.size)
				add(null);
			return null;
		}
		return set(index, element);
	}

	private boolean batchRemove(Collection<?> c, boolean complement) {
		final Object[] elementData = this.elementData;
		int r = 0, w = 0;
		boolean modified = false;
		try {
			for (; r < size; r++)
				if (c.contains(elementData[r]) == complement)
					elementData[w++] = elementData[r];
		} finally {
			// Preserve behavioral compatibility with AbstractCollection,
			// even if c.contains() throws.
			if (r != size) {
				System.arraycopy(elementData, r, elementData, w, size - r);
				w += size - r;
			}
			if (w != size) {
				for (int i = w; i < size; i++)
					elementData[i] = null;
				modCount += size - w;
				size = w;
				modified = true;
			}
		}
		return modified;
	}

	/**
	 * Removes all of the elements from this list. The list will be empty after
	 * this call returns.
	 */
	@Override
	public void clear() {
		modCount++;

		// Let gc do its work
		for (int i = 0; i < size; i++)
			elementData[i] = null;

		size = 0;
	}

	/**
	 * Returns a shallow copy of this <tt>AArrayList</tt> instance. (The
	 * elements themselves are not copied.)
	 * 
	 * @return a clone of this <tt>AArrayList</tt> instance
	 */
	@Override
	public Object clone() {
		@SuppressWarnings("unchecked")
		AArrayList<E> v = (AArrayList<E>) super.clone();
		v.elementData = Arrays.copyOf(elementData, size);
		v.modCount = 0;
		return v;

	}

	// Positional Access Operations

	/**
	 * Returns <tt>true</tt> if this list contains the specified element. More
	 * formally, returns <tt>true</tt> if and only if this list contains at
	 * least one element <tt>e</tt> such that
	 * <tt>(o==null&nbsp;?&nbsp;e==null&nbsp;:&nbsp;o.equals(e))</tt>.
	 * 
	 * @param o
	 *            element whose presence in this list is to be tested
	 * @return <tt>true</tt> if this list contains the specified element
	 */
	@Override
	public boolean contains(Object o) {
		return indexOf(o) >= 0;
	}

	@SuppressWarnings("unchecked")
	E elementData(int index) {// FIXME
		return (E) elementData[index];
	}

	/**
	 * Increases the capacity of this <tt>AArrayList</tt> instance, if
	 * necessary, to ensure that it can hold at least the number of elements
	 * specified by the minimum capacity argument.
	 * 
	 * @param minCapacity
	 *            the desired minimum capacity
	 */
	@Override
	public void ensureCapacity(int minCapacity) {
		if (minCapacity > 0)
			ensureCapacityInternal(minCapacity);
	}

	private void ensureCapacityInternal(int minCapacity) {
		modCount++;
		// overflow-conscious code
		if (minCapacity - elementData.length > 0)
			grow(minCapacity);
	}

	/*
	 * Private remove method that skips bounds checking and does not return the
	 * value removed.
	 */
	private void fastRemove(int index) {
		modCount++;
		int numMoved = size - index - 1;
		if (numMoved > 0)
			System.arraycopy(elementData, index + 1, elementData, index,
					numMoved);
		elementData[--size] = null; // Let gc do its work
	}

	/**
	 * Returns the element at the specified position in this list.
	 * 
	 * @param index
	 *            index of the element to return
	 * @return the element at the specified position in this list
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	@Override
	public E get(int index) {
		rangeCheck(index);

		return elementData(index);
	}

	/**
	 * Increases the capacity to ensure that it can hold at least the number of
	 * elements specified by the minimum capacity argument.
	 * 
	 * @param minCapacity
	 *            the desired minimum capacity
	 */
	private void grow(int minCapacity) {
		// overflow-conscious code
		int oldCapacity = elementData.length;
		int newCapacity = oldCapacity + (oldCapacity >> 1);
		if (newCapacity - minCapacity < 0)
			newCapacity = minCapacity;
		if (newCapacity - AArrayList.MAX_ARRAY_SIZE > 0)
			newCapacity = AArrayList.hugeCapacity(minCapacity);
		// minCapacity is usually close to size, so this is a win:
		elementData = Arrays.copyOf(elementData, newCapacity);
	}

	/**
	 * Returns the index of the first occurrence of the specified element in
	 * this list, or -1 if this list does not contain the element. More
	 * formally, returns the lowest index <tt>i</tt> such that
	 * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
	 * or -1 if there is no such index.
	 */
	@Override
	public int indexOf(Object o) {
		if (o == null) {
			for (int i = 0; i < size; i++)
				if (elementData[i] == null)
					return i;
		} else
			for (int i = 0; i < size; i++)
				if (o.equals(elementData[i]))
					return i;
		return -1;
	}

	/**
	 * Returns <tt>true</tt> if this list contains no elements.
	 * 
	 * @return <tt>true</tt> if this list contains no elements
	 */
	@Override
	public boolean isEmpty() {
		return size == 0;
	}

	/**
	 * Returns an iterator over the elements in this list in proper sequence.
	 * 
	 * <p>
	 * The returned iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
	 * 
	 * @return an iterator over the elements in this list in proper sequence
	 */
	@Override
	public Iterator<E> iterator() {
		return new Itr();
	}

	/**
	 * Returns the index of the last occurrence of the specified element in this
	 * list, or -1 if this list does not contain the element. More formally,
	 * returns the highest index <tt>i</tt> such that
	 * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>,
	 * or -1 if there is no such index.
	 */
	@Override
	public int lastIndexOf(Object o) {
		if (o == null) {
			for (int i = size - 1; i >= 0; i--)
				if (elementData[i] == null)
					return i;
		} else
			for (int i = size - 1; i >= 0; i--)
				if (o.equals(elementData[i]))
					return i;
		return -1;
	}

	/**
	 * Returns a list iterator over the elements in this list (in proper
	 * sequence).
	 * 
	 * <p>
	 * The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
	 * 
	 * @see #listIterator(int)
	 */
	@Override
	public ListIterator<E> listIterator() {
		return new ListItr(0);
	}

	/**
	 * Returns a list iterator over the elements in this list (in proper
	 * sequence), starting at the specified position in the list. The specified
	 * index indicates the first element that would be returned by an initial
	 * call to {@link ListIterator#next next}. An initial call to
	 * {@link ListIterator#previous previous} would return the element with the
	 * specified index minus one.
	 * 
	 * <p>
	 * The returned list iterator is <a href="#fail-fast"><i>fail-fast</i></a>.
	 * 
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	@Override
	public ListIterator<E> listIterator(int index) {
		if (index < 0 || index > size)
			throw new IndexOutOfBoundsException("Index: " + index);
		return new ListItr(index);
	}

	/**
	 * Constructs an IndexOutOfBoundsException detail message. Of the many
	 * possible refactorings of the error handling code, this "outlining"
	 * performs best with both server and client VMs.
	 */
	private String outOfBoundsMsg(int index) {
		return "Index: " + index + ", Size: " + size;
	}

	/**
	 * Checks if the given index is in range. If not, throws an appropriate
	 * runtime exception. This method does *not* check if the index is negative:
	 * It is always used immediately prior to an array access, which throws an
	 * ArrayIndexOutOfBoundsException if index is negative.
	 */
	private void rangeCheck(int index) {
		if (index >= size)
			throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
	}

	/**
	 * A version of rangeCheck used by add and addAll.
	 */
	private void rangeCheckForAdd(int index) {
		if (index > size || index < 0)
			throw new IndexOutOfBoundsException(outOfBoundsMsg(index));
	}

	/**
	 * Reconstitute the <tt>AArrayList</tt> instance from a stream (that is,
	 * deserialize it).
	 */
	private void readObject(java.io.ObjectInputStream s)
			throws java.io.IOException, ClassNotFoundException {
		// Read in size, and any hidden stuff
		s.defaultReadObject();

		// Read in array length and allocate array
		int arrayLength = s.readInt();
		Object[] a = elementData = new Object[arrayLength];

		// Read in all elements in the proper order.
		for (int i = 0; i < size; i++)
			a[i] = s.readObject();
	}

	/**
	 * Removes the element at the specified position in this list. Shifts any
	 * subsequent elements to the left (subtracts one from their indices).
	 * 
	 * @param index
	 *            the index of the element to be removed
	 * @return the element that was removed from the list
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	@Override
	public E remove(int index) {
		rangeCheck(index);

		modCount++;
		E oldValue = elementData(index);

		int numMoved = size - index - 1;
		if (numMoved > 0)
			System.arraycopy(elementData, index + 1, elementData, index,
					numMoved);
		elementData[--size] = null; // Let gc do its work

		return oldValue;
	}

	/**
	 * Removes the first occurrence of the specified element from this list, if
	 * it is present. If the list does not contain the element, it is unchanged.
	 * More formally, removes the element with the lowest index <tt>i</tt> such
	 * that
	 * <tt>(o==null&nbsp;?&nbsp;get(i)==null&nbsp;:&nbsp;o.equals(get(i)))</tt>
	 * (if such an element exists). Returns <tt>true</tt> if this list contained
	 * the specified element (or equivalently, if this list changed as a result
	 * of the call).
	 * 
	 * @param o
	 *            element to be removed from this list, if present
	 * @return <tt>true</tt> if this list contained the specified element
	 */
	@Override
	public boolean remove(Object o) {
		if (o == null) {
			for (int index = 0; index < size; index++)
				if (elementData[index] == null) {
					fastRemove(index);
					return true;
				}
		} else
			for (int index = 0; index < size; index++)
				if (o.equals(elementData[index])) {
					fastRemove(index);
					return true;
				}
		return false;
	}

	/**
	 * Removes from this list all of its elements that are contained in the
	 * specified collection.
	 * 
	 * @param c
	 *            collection containing elements to be removed from this list
	 * @return {@code true} if this list changed as a result of the call
	 * @throws ClassCastException
	 *             if the class of an element of this list is incompatible with
	 *             the specified collection (optional)
	 * @throws NullPointerException
	 *             if this list contains a null element and the specified
	 *             collection does not permit null elements (optional), or if
	 *             the specified collection is null
	 * @see Collection#contains(Object)
	 */
	@Override
	public boolean removeAll(Collection<?> c) {
		return batchRemove(c, false);
	}

	/**
	 * Removes from this list all of the elements whose index is between
	 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. Shifts any
	 * succeeding elements to the left (reduces their index). This call shortens
	 * the list by {@code (toIndex - fromIndex)} elements. (If
	 * {@code toIndex==fromIndex}, this operation has no effect.)
	 * 
	 * @throws IndexOutOfBoundsException
	 *             if {@code fromIndex} or {@code toIndex} is out of range (
	 *             {@code fromIndex < 0 ||
	 *          fromIndex >= size() ||
	 *          toIndex > size() ||
	 *          toIndex < fromIndex})
	 */
	@Override
	protected void removeRange(int fromIndex, int toIndex) {
		modCount++;
		int numMoved = size - toIndex;
		System.arraycopy(elementData, toIndex, elementData, fromIndex, numMoved);

		// Let gc do its work
		int newSize = size - (toIndex - fromIndex);
		while (size != newSize)
			elementData[--size] = null;
	}

	/**
	 * Retains only the elements in this list that are contained in the
	 * specified collection. In other words, removes from this list all of its
	 * elements that are not contained in the specified collection.
	 * 
	 * @param c
	 *            collection containing elements to be retained in this list
	 * @return {@code true} if this list changed as a result of the call
	 * @throws ClassCastException
	 *             if the class of an element of this list is incompatible with
	 *             the specified collection (optional)
	 * @throws NullPointerException
	 *             if this list contains a null element and the specified
	 *             collection does not permit null elements (optional), or if
	 *             the specified collection is null
	 * @see Collection#contains(Object)
	 */
	@Override
	public boolean retainAll(Collection<?> c) {
		return batchRemove(c, true);
	}

	/**
	 * Replaces the element at the specified position in this list with the
	 * specified element.
	 * 
	 * @param index
	 *            index of the element to replace
	 * @param element
	 *            element to be stored at the specified position
	 * @return the element previously at the specified position
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 */
	@Override
	public E set(int index, E element) {
		rangeCheck(index);

		E oldValue = elementData(index);
		elementData[index] = element;
		return oldValue;
	}

	/**
	 * Returns the number of elements in this list.
	 * 
	 * @return the number of elements in this list
	 */
	@Override
	public int size() {
		return size;
	}

	/**
	 * Returns a view of the portion of this list between the specified
	 * {@code fromIndex}, inclusive, and {@code toIndex}, exclusive. (If
	 * {@code fromIndex} and {@code toIndex} are equal, the returned list is
	 * empty.) The returned list is backed by this list, so non-structural
	 * changes in the returned list are reflected in this list, and vice-versa.
	 * The returned list supports all of the optional list operations.
	 * 
	 * <p>
	 * This method eliminates the need for explicit range operations (of the
	 * sort that commonly exist for arrays). Any operation that expects a list
	 * can be used as a range operation by passing a subList view instead of a
	 * whole list. For example, the following idiom removes a range of elements
	 * from a list:
	 * 
	 * <pre>
	 * list.subList(from, to).clear();
	 * </pre>
	 * 
	 * Similar idioms may be constructed for {@link #indexOf(Object)} and
	 * {@link #lastIndexOf(Object)}, and all of the algorithms in the
	 * {@link Collections} class can be applied to a subList.
	 * 
	 * <p>
	 * The semantics of the list returned by this method become undefined if the
	 * backing list (i.e., this list) is <i>structurally modified</i> in any way
	 * other than via the returned list. (Structural modifications are those
	 * that change the size of this list, or otherwise perturb it in such a
	 * fashion that iterations in progress may yield incorrect results.)
	 * 
	 * @throws IndexOutOfBoundsException
	 *             {@inheritDoc}
	 * @throws IllegalArgumentException
	 *             {@inheritDoc}
	 */
	@Override
	public List<E> subList(int fromIndex, int toIndex) {
		AArrayList.subListRangeCheck(fromIndex, toIndex, size);
		return new SubList(this, 0, fromIndex, toIndex);
	}

	/**
	 * Returns an array containing all of the elements in this list in proper
	 * sequence (from first to last element).
	 * 
	 * <p>
	 * The returned array will be "safe" in that no references to it are
	 * maintained by this list. (In other words, this method must allocate a new
	 * array). The caller is thus free to modify the returned array.
	 * 
	 * <p>
	 * This method acts as bridge between array-based and collection-based APIs.
	 * 
	 * @return an array containing all of the elements in this list in proper
	 *         sequence
	 */
	@Override
	public Object[] toArray() {
		return Arrays.copyOf(elementData, size);
	}

	/**
	 * Returns an array containing all of the elements in this list in proper
	 * sequence (from first to last element); the runtime type of the returned
	 * array is that of the specified array. If the list fits in the specified
	 * array, it is returned therein. Otherwise, a new array is allocated with
	 * the runtime type of the specified array and the size of this list.
	 * 
	 * <p>
	 * If the list fits in the specified array with room to spare (i.e., the
	 * array has more elements than the list), the element in the array
	 * immediately following the end of the collection is set to <tt>null</tt>.
	 * (This is useful in determining the length of the list <i>only</i> if the
	 * caller knows that the list does not contain any null elements.)
	 * 
	 * @param a
	 *            the array into which the elements of the list are to be
	 *            stored, if it is big enough; otherwise, a new array of the
	 *            same runtime type is allocated for this purpose.
	 * @return an array containing the elements of the list
	 * @throws ArrayStoreException
	 *             if the runtime type of the specified array is not a supertype
	 *             of the runtime type of every element in this list
	 * @throws NullPointerException
	 *             if the specified array is null
	 */
	@Override
	@SuppressWarnings("unchecked")
	public <T> T[] toArray(T[] a) {
		if (a.length < size)
			// Make a new array of a's runtime type, but my contents:
			return (T[]) Arrays.copyOf(elementData, size, a.getClass());
		System.arraycopy(elementData, 0, a, 0, size);
		if (a.length > size)
			a[size] = null;
		return a;
	}

	/**
	 * Trims the capacity of this <tt>AArrayList</tt> instance to be the list's
	 * current size. An application can use this operation to minimize the
	 * storage of an <tt>AArrayList</tt> instance.
	 */
	@Override
	public void trimToSize() {
		modCount++;
		int oldCapacity = elementData.length;
		if (size < oldCapacity)
			elementData = Arrays.copyOf(elementData, size);
	}

	/**
	 * Save the state of the <tt>AArrayList</tt> instance to a stream (that is,
	 * serialize it).
	 * 
	 * @serialData The length of the array backing the <tt>AArrayList</tt>
	 *             instance is emitted (int), followed by all of its elements
	 *             (each an <tt>Object</tt>) in the proper order.
	 */
	private void writeObject(java.io.ObjectOutputStream s)
			throws java.io.IOException {
		// Write out element count, and any hidden stuff
		int expectedModCount = modCount;
		s.defaultWriteObject();

		// Write out array length
		s.writeInt(elementData.length);

		// Write out all elements in the proper order.
		for (int i = 0; i < size; i++)
			s.writeObject(elementData[i]);

		if (modCount != expectedModCount)
			throw new ConcurrentModificationException();

	}
}
